Project #36255 - Statistics

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Statistics Assignment 11: Working with Two Proportions

Directions: Complete the assignment on your own paper. Clearly label each answer. Your answers for this assignment must include reasons; simply stating the answer without justification will earn partial credit. (30 points)

A study of “adverse symptoms” in users of over-the-counter pain relief medications assigned subjects at random to one of two common pain relievers: acetaminophen and ibuprofen. In all, 650 subjects took acetaminophen, and 44 experienced some adverse symptom. Of the 347 subjects who took ibuprofen, 49 had an adverse symptom. We want to assess the evidence that the two pain relievers differ in the proportion of people who experience an adverse symptom.

1.Identify the populations and parameters of interest. Then state hypotheses. (3 points)

2.State and verify conditions for carrying out a significance test. (3 points)

3.Calculate the test statistic and the P-value. (4 points)

4.What conclusion would you draw? (2 points)

5.Construct and interpret a 90% confidence interval for the size of the difference. (4 points)

A study of chromosome abnormalities and criminality examined data from 4,124 males born in Copenhagen. Each man was classified as having a criminal record or not, using the registers maintained in the local police offices. Each was also classified as having the normal male XY chromosome pair or one of the abnormalities XYY or XXY. Of the 4,096 men with normal chromosomes 381 had criminal records, while 8 of the 28 men with normal chromosomes had criminal records. Some experts believe chromosome abnormalities are associated with increased criminality.

6.Do these data lend support to this belief? Perform a significance test to answer this question. (10 points)

7.Construct and interpret a 95% confidence interval for the difference in proportions. (4 points)